1 /* 2 * USB Serial Console driver 3 * 4 * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License version 8 * 2 as published by the Free Software Foundation. 9 * 10 * Thanks to Randy Dunlap for the original version of this code. 11 * 12 */ 13 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 16 #include <linux/kernel.h> 17 #include <linux/slab.h> 18 #include <linux/tty.h> 19 #include <linux/console.h> 20 #include <linux/serial.h> 21 #include <linux/usb.h> 22 #include <linux/usb/serial.h> 23 24 struct usbcons_info { 25 int magic; 26 int break_flag; 27 struct usb_serial_port *port; 28 }; 29 30 static struct usbcons_info usbcons_info; 31 static struct console usbcons; 32 33 /* 34 * ------------------------------------------------------------ 35 * USB Serial console driver 36 * 37 * Much of the code here is copied from drivers/char/serial.c 38 * and implements a phony serial console in the same way that 39 * serial.c does so that in case some software queries it, 40 * it will get the same results. 41 * 42 * Things that are different from the way the serial port code 43 * does things, is that we call the lower level usb-serial 44 * driver code to initialize the device, and we set the initial 45 * console speeds based on the command line arguments. 46 * ------------------------------------------------------------ 47 */ 48 49 static const struct tty_operations usb_console_fake_tty_ops = { 50 }; 51 52 /* 53 * The parsing of the command line works exactly like the 54 * serial.c code, except that the specifier is "ttyUSB" instead 55 * of "ttyS". 56 */ 57 static int usb_console_setup(struct console *co, char *options) 58 { 59 struct usbcons_info *info = &usbcons_info; 60 int baud = 9600; 61 int bits = 8; 62 int parity = 'n'; 63 int doflow = 0; 64 int cflag = CREAD | HUPCL | CLOCAL; 65 char *s; 66 struct usb_serial *serial; 67 struct usb_serial_port *port; 68 int retval; 69 struct tty_struct *tty = NULL; 70 struct ktermios dummy; 71 72 if (options) { 73 baud = simple_strtoul(options, NULL, 10); 74 s = options; 75 while (*s >= '0' && *s <= '9') 76 s++; 77 if (*s) 78 parity = *s++; 79 if (*s) 80 bits = *s++ - '0'; 81 if (*s) 82 doflow = (*s++ == 'r'); 83 } 84 85 /* Sane default */ 86 if (baud == 0) 87 baud = 9600; 88 89 switch (bits) { 90 case 7: 91 cflag |= CS7; 92 break; 93 default: 94 case 8: 95 cflag |= CS8; 96 break; 97 } 98 switch (parity) { 99 case 'o': case 'O': 100 cflag |= PARODD; 101 break; 102 case 'e': case 'E': 103 cflag |= PARENB; 104 break; 105 } 106 co->cflag = cflag; 107 108 /* 109 * no need to check the index here: if the index is wrong, console 110 * code won't call us 111 */ 112 port = usb_serial_port_get_by_minor(co->index); 113 if (port == NULL) { 114 /* no device is connected yet, sorry :( */ 115 pr_err("No USB device connected to ttyUSB%i\n", co->index); 116 return -ENODEV; 117 } 118 serial = port->serial; 119 120 retval = usb_autopm_get_interface(serial->interface); 121 if (retval) 122 goto error_get_interface; 123 124 tty_port_tty_set(&port->port, NULL); 125 126 info->port = port; 127 128 ++port->port.count; 129 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) { 130 if (serial->type->set_termios) { 131 /* 132 * allocate a fake tty so the driver can initialize 133 * the termios structure, then later call set_termios to 134 * configure according to command line arguments 135 */ 136 tty = kzalloc(sizeof(*tty), GFP_KERNEL); 137 if (!tty) { 138 retval = -ENOMEM; 139 goto reset_open_count; 140 } 141 kref_init(&tty->kref); 142 tty->driver = usb_serial_tty_driver; 143 tty->index = co->index; 144 init_ldsem(&tty->ldisc_sem); 145 INIT_LIST_HEAD(&tty->tty_files); 146 kref_get(&tty->driver->kref); 147 tty->ops = &usb_console_fake_tty_ops; 148 if (tty_init_termios(tty)) { 149 retval = -ENOMEM; 150 goto put_tty; 151 } 152 tty_port_tty_set(&port->port, tty); 153 } 154 155 /* only call the device specific open if this 156 * is the first time the port is opened */ 157 retval = serial->type->open(NULL, port); 158 if (retval) { 159 dev_err(&port->dev, "could not open USB console port\n"); 160 goto fail; 161 } 162 163 if (serial->type->set_termios) { 164 tty->termios.c_cflag = cflag; 165 tty_termios_encode_baud_rate(&tty->termios, baud, baud); 166 memset(&dummy, 0, sizeof(struct ktermios)); 167 serial->type->set_termios(tty, port, &dummy); 168 169 tty_port_tty_set(&port->port, NULL); 170 tty_kref_put(tty); 171 } 172 set_bit(ASYNCB_INITIALIZED, &port->port.flags); 173 } 174 /* Now that any required fake tty operations are completed restore 175 * the tty port count */ 176 --port->port.count; 177 /* The console is special in terms of closing the device so 178 * indicate this port is now acting as a system console. */ 179 port->port.console = 1; 180 181 mutex_unlock(&serial->disc_mutex); 182 return retval; 183 184 fail: 185 tty_port_tty_set(&port->port, NULL); 186 put_tty: 187 tty_kref_put(tty); 188 reset_open_count: 189 port->port.count = 0; 190 usb_autopm_put_interface(serial->interface); 191 error_get_interface: 192 usb_serial_put(serial); 193 mutex_unlock(&serial->disc_mutex); 194 return retval; 195 } 196 197 static void usb_console_write(struct console *co, 198 const char *buf, unsigned count) 199 { 200 static struct usbcons_info *info = &usbcons_info; 201 struct usb_serial_port *port = info->port; 202 struct usb_serial *serial; 203 int retval = -ENODEV; 204 205 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED) 206 return; 207 serial = port->serial; 208 209 if (count == 0) 210 return; 211 212 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count); 213 214 if (!port->port.console) { 215 dev_dbg(&port->dev, "%s - port not opened\n", __func__); 216 return; 217 } 218 219 while (count) { 220 unsigned int i; 221 unsigned int lf; 222 /* search for LF so we can insert CR if necessary */ 223 for (i = 0, lf = 0 ; i < count ; i++) { 224 if (*(buf + i) == 10) { 225 lf = 1; 226 i++; 227 break; 228 } 229 } 230 /* pass on to the driver specific version of this function if 231 it is available */ 232 retval = serial->type->write(NULL, port, buf, i); 233 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval); 234 if (lf) { 235 /* append CR after LF */ 236 unsigned char cr = 13; 237 retval = serial->type->write(NULL, port, &cr, 1); 238 dev_dbg(&port->dev, "%s - write cr: %d\n", 239 __func__, retval); 240 } 241 buf += i; 242 count -= i; 243 } 244 } 245 246 static struct tty_driver *usb_console_device(struct console *co, int *index) 247 { 248 struct tty_driver **p = (struct tty_driver **)co->data; 249 250 if (!*p) 251 return NULL; 252 253 *index = co->index; 254 return *p; 255 } 256 257 static struct console usbcons = { 258 .name = "ttyUSB", 259 .write = usb_console_write, 260 .device = usb_console_device, 261 .setup = usb_console_setup, 262 .flags = CON_PRINTBUFFER, 263 .index = -1, 264 .data = &usb_serial_tty_driver, 265 }; 266 267 void usb_serial_console_disconnect(struct usb_serial *serial) 268 { 269 if (serial && serial->port && serial->port[0] 270 && serial->port[0] == usbcons_info.port) { 271 usb_serial_console_exit(); 272 usb_serial_put(serial); 273 } 274 } 275 276 void usb_serial_console_init(int minor) 277 { 278 if (minor == 0) { 279 /* 280 * Call register_console() if this is the first device plugged 281 * in. If we call it earlier, then the callback to 282 * console_setup() will fail, as there is not a device seen by 283 * the USB subsystem yet. 284 */ 285 /* 286 * Register console. 287 * NOTES: 288 * console_setup() is called (back) immediately (from 289 * register_console). console_write() is called immediately 290 * from register_console iff CON_PRINTBUFFER is set in flags. 291 */ 292 pr_debug("registering the USB serial console.\n"); 293 register_console(&usbcons); 294 } 295 } 296 297 void usb_serial_console_exit(void) 298 { 299 if (usbcons_info.port) { 300 unregister_console(&usbcons); 301 usbcons_info.port->port.console = 0; 302 usbcons_info.port = NULL; 303 } 304 } 305 306